This invention relates to centrifuges and methods of centrifuging of the type used to separate mixtures of generally flowable components having differing specific gravities on a continuous process basis. More specifically, this invention relates to an improved centrifuge and method of centrifuging of the type which uses a rotating separation chamber to segregate the component elements of an oil-water-particulate contaminant mixture into isolated flow paths, which centrifuge and method includes use of an automatic purging element associated with the separation chamber and responsive to the rotational speed thereof to automatically purge the separation chamber of particulate contaminant buildup.
While the struggle to reduce dependence upon oil products continues, the stark reality is that the world's minimum daily requirement for these goods will not diminish during the many years required for the development of viable alternatives. Since the cost of crude oil is not easily controlled, the end user cost factors flowing from excessive labor and processing expense of conventional crude and reusable oil processes have been targeted for much needed technical cost saving solutions. This invention was borne at least in part, as a result of the attempts to aid the oil industry and the consumers of its products, in their search for one of these solutions, i.e. a more economical way to separate the oil water and particulate mixture that is obtained at the well head or from recycling sources into usable oil and disposable contaminants.
Crude oil obtained at the well head is typically placed in settling tanks for an extended period of time to allow particulate contaminants to filter out. It is then heated to separate the oil and water mixture. Oil-water mixtures which are to be recycled are also typically preprocessed in a similar manner.
As the cost of energy increases so too does the cost of heating crude or recyclable oil. As time becomes more expensive and the demand for usable oil more immediate, the time consuming settling process becomes more intolerable. Therefore, the less costly solution which has presented itself is the use of centrifuges to separate oil water mixtures. This is particularly true since even after conventional heating, the oil still contains fine particulate contaminants which must be isolated before further processing can continue.
In addition to addressing the energy needs of the oil consuming public, the present invention also tackles the complex environmental problems presented by ship bourne oil lubricated machinery by providing an economical tool for separating bilge oil-water-particulate mixtures into disposable water and particulate flows which may be safely dumped, and, oil flows which may be stored and possibly reused.
Centrifuges are well known in the prior art and typically comprise a separation chamber which is rotatable to cause isolation of the individual components of the mixture being centrifuged. However, for the most part these well known centrifuges are limited in application to batch process operations where the mixture is placed in a separate vessel and then placed in the separation chamber. Inherent in the use of these well known devices is the expense of excessive downtime and labor requirements. The economic infeasibility of such operations has condemned these units to laboratory settings.
Of the prior art centrifuges which are operable on a continuous process basis i.e. capable of handling a sustained flow of mixture, a first type failed to address the problem of automatically purging the system of heavy component contaminant buildup on the separation chamber inner surfaces by other than costly manual methods of repair and reconstruction. A second type provided structural elements which purged the system of particulate contaminants, but required cessation of fractioning operations during purging. These type devices, while more economically feasible in industrial settings nonetheless still required the frequent shutdown problems which this invention addresses.